Discovery of a new quadruply lensed QSO: HS 0810+2554 - A brighter twin to PG 1115+080

Abstract

We announce the probable discovery of a new very bright gravitationally lensed QSO, HS 0810+2554 (z=1.50, V=15.3). The gravitational lens character has been discovered serendipitously by means of short (12 times 1 s) HST/STIS target acquisition images. The coadded images show a close bright double A (V=16.0) and B (16.7) separated by 0.25 arcsec plus two fainter images C (17.4) and D (18.8). There is also evidence for a lens galaxy in the center of the images which is fainter than A by a factor of le 30 at 7150 Å. The image configuration resembles very much that of PG 1115+080 except that in HS 0810+2554 image splittings (<=1'') are smaller by a factor of ~ 2.5 and HS 0810+2554 is brighter by ~ 1^{m}. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by Aura, Inc., under NASA contract NAS 5-26 555 and on observations at the German - Spanish Astronomical Center (DSAZ) on Calar Alto, Spain.